Description: Made from high quality HSS steel, last longer than regular steel countersink bits The bits can be used on wood, plastic, aluminium, insulating plate and PVC board, etc 4241 HSS steel only suit for pieces with low hardness, do not use for metal with this bits This set features a quick-change shank design for convenience Commonly used Sizes Including 2-5mm ,5-10mm, 10-15mm, 15-20mm Specification: Material: 4241 HSS / High Speed Steel Dimension: 2mm-5mm: Handle: 6mm/ 0.24inch; Diameter: 9.7mm/ 0.38inch 5mm-10mm: Handle: 8mm/ 0.31inch; Diameter: 14mm/ 0.55inch 10mm-15mm: Handle: 10mm/ 0.39inch; Diameter: 21mm/ 0.83inch 15mm-20mm: Handle: 12mm/ 0.47inch; Diameter: 28mm/ 1.10inch Package Includes: 1x Set (4 pieces) Countersink Drill Bit Note: The colors may be different for the different display, please understand Please allow 1-3mm error due to manual measurement, make sure you do not mind before you bid